I'm struggling with kstars, it always crashes when I try to polar align. Captures the 1st pic, solves it, gets WCS then just quits. Happens everytime in the exact same spot (oddly, it used to happen after the 3rd image was captured, but now it's the first one.
Kstars v3.5.0 Stable, INDI Library: 1.8.7 (Code v1.8.7. Protocol 1.7)
All installled with Astroberry and updated from the repo using apt.
Using a RPi4 with 8Gb RAM.
Astroberry updated just today or yesterday to KStars 3.5.2 and now has the newest version of the Polar Align routine.
I hope that fixes you problem. If not, maybe post in the Ekos section, where you might be more likely to get the attention of Hy (author of the PA routine).
I had the same problem, the way I solved it was to switch to a 64 bit OS (Ubuntu 20.1). I have the Rpi4 also with 8 Gb of Ram, but the 32 bit Raspbian OS just was not handling the memory needed for loading the index files and plate solving. You could try plate solving using only 1 thread and uncheck the box to load all index files in memory. But giving up the Astroberry server and just running Kstars/Ekos under Ubuntu has been well worth the trade. I have imaged for over 10 hours over several nights and not one crash, anywhere.
I have a thread on this forum for loading the Ubuntu OS on the Rpi. It is wonderful to have the software behave as you expect it night after night.